Co-located locationing technologies

ABSTRACT

A method and apparatus for a co-located Radio Frequency Identification (RFID) device and ultrasonic device includes an RFID reader loop antenna element oriented parallel to a reflector panel. An ultrasonic emitter is disposed through an aperture in the reflector panel with a horn that extends through the loop element. The horn can serve as a mounting structure for the antenna element. A diameter of the aperture is less than one-quarter wavelength of an operating frequency of the RFID reader loop antenna element. The aperture is located in the reflector panel near a minimum E-field area of the RFID reader loop antenna element.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/492,110, filed on Sep. 22, 2014, and incorporated herein by referencein its entirety.

BACKGROUND

The use of locationing technology is expanding in local areaenvironments, such as a retail environment, a factory environment, awarehouse environment, etc. In addition, there are a variety ofdifferent locationing technologies available (e.g. Radio FrequencyIdentification (RFID), ultrasonic signals, RF signals, video, etc.) thatcan be used for different purposes. These different purposes can resultin the need for incorporating combinations of these differentlocationing technologies within the same environment. However, some ofthese locationing technologies can be bulky, and providing independentinstallation of each locationing technology could end up duplicatingother systems, such as supplying separate network communicationinfrastructure for each locationing technology.

As a result, in a commercial environment there may be several differentlocationing technologies being used, each using their own networkcommunication infrastructure. For example, in a Radio FrequencyIdentification (RFID) application, fixed RFID readers may be mountedoverhead (e.g., ceiling mounted) in several positions and orientationsthroughout the environment, in order to read and locate any RFID tagwithin the environment. Also, in an ultrasonic locationing system, fixedultrasonic emitters may be mounted overhead (e.g., ceiling mounted) inseveral positions throughout the environment, in order to locate andtrack any mobile device within the environment. These overheadconfigurations offer several advantages such as fewer physical signalobstructions, ease of access to wiring in a ceiling, tamper resistance,safety, and the like. Each of these applications can require multipleantennas/emitters and circuitry housings disposed throughout theenvironment. Therefore, it can be desirable to combine the networkinfrastructure for different locationing systems into a common housingor into other available housings such as video cameras, etc. However,such combinations have disadvantages.

For example, combining different locationing systems into a commonhousing will increase the size of the housing, making installation moredifficult and appearing more obtrusive. In particular, in order to getfull 360 degree coverage, an RFID locationing device can use eight RFIDantennas distributed outwardly every 45 degrees around a circle. Whereasan ultrasonic locationing system can use four ultrasonic emitters,positioned and oriented every 90 degrees around a circle. Because anoversized combined product is obviously undesirable, a compactmechanical package combining these two technologies is desirable, andany opportunity to combine the two in a shared space would be ofbenefit.

Accordingly, there is a need for a technique to physically combinedifferent locationing technologies that overcome the aforementionedlimitations.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, together with the detailed description below, are incorporated inand form part of the specification, and serve to further illustrateembodiments of concepts that include the claimed invention, and explainvarious principles and advantages of those embodiments.

FIG. 1 is a simplified block diagram of an RFID reader and antennaconfiguration, in accordance with some embodiments of the presentinvention.

FIG. 2 is a simplified block diagram of an ultrasonic emitterconfiguration, in accordance with some embodiments of the presentinvention.

FIG. 3 is a perspective view of an assembly of one co-located RFIDantenna and ultrasonic emitter combination for the devices of FIGS. 1and 2.

FIG. 4 is a cut-away view of the embodiment of FIG. 3.

FIG. 5 is a perspective view of a housing including the co-located RFIDantennas and ultrasonic emitters of FIGS. 1 and 2.

FIG. 6 is a perspective view of an example environment utilizing theantenna arrangement of FIG. 5.

FIG. 7 shows a flowchart of a method in accordance with some embodimentsof the present invention.

FIG. 8 shows a mobile device and a theoretical listening plane inaccordance with some embodiments of the present invention.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the present invention.

The apparatus and method components have been represented whereappropriate by conventional symbols in the drawings, showing only thosespecific details that are pertinent to understanding the embodiments ofthe present invention so as not to obscure the disclosure with detailsthat will be readily apparent to those of ordinary skill in the arthaving the benefit of the description herein.

DETAILED DESCRIPTION

In various exemplary embodiments, the present invention provides atechnique for combining and co-locating different locationingtechnologies into a common housing without a significant increase inoverall size. The present invention provides an overhead combination ofdifferent locationing technologies in a small and lightweightarrangement, where the physical size of the combination arrangement iskept to a minimum so that the system is unobtrusive, easy to assemble,easy to install, integrate, and maintain, and can allow for otherfeatures, such as a security camera, wireless communication, etc.

For example, each of the locationing technologies can communicate with aremote server using a shared, common wireless communication system (notshown). It should be recognized that the present invention can beapplied using one or more wireless communication technologies such as,but are not limited to: RF; IrDA (infrared); Bluetooth; ZigBee (andother variants of the IEEE 802.15 protocol); IEEE 802.11 (anyvariation); other RFID frequency bands, such as HF and LF; IEEE 802.16(WiMAX or any other variation); Universal Mobile TelecommunicationsSystem (UMTS); Code Division Multiple Access (CDMA) including allvariants; Global System for Mobile Communications (GSM) and allvariants; Time division multiple access (TDMA) and all variants; DirectSequence Spread Spectrum; Frequency Hopping Spread Spectrum;wireless/cordless telecommunication protocols; wireless home networkcommunication protocols; paging network protocols; magnetic induction;satellite data communication protocols; wireless hospital or health carefacility network protocols such as those operating in the WMTS bands;GPRS; and proprietary wireless data communication protocols such asvariants of Wireless USB.

In general, the RFID reader is configured to provide communicationbetween the RFID reader and nearby RFID tags. For example, the RFIDreader “interrogates” RFID tags, and receives signals back from the tagsin response to the interrogation. The reader is sometimes termed as“reader interrogator” or simply “interrogator.” In an exemplaryembodiment, the RFID reader may include, without limitation one or moreof: a processor, a communication module, memory, and at least oneantenna. The elements of the RFID reader may be interconnected togetherusing a communication bus or another suitable interconnectionarrangement that facilitates communication between the various elementsof the RFID reader.

The ultrasonic locationing technology is configured to provide timesignals between an ultrasonic emitter and a mobile device. For example,the mobile device can receive ultrasonic signals from differentemitters, measure the timing of each of these signals, and usetriangulation or other techniques to establish its position within theenvironment. In an exemplary embodiment, the ultrasonic locationingtechnology may also include, without limitation one or more of: aprocessor, a controller, a communication module, memory, and a pluralityof ultrasonic emitters.

Both of the RFID reader and ultrasonic controller can share the samecommunication module, which can include components enablingcommunication on a wired or wireless network. For example, thecommunication module may include a wired Ethernet interface or wirelessaccess point to communicate information about RFID tags and ultrasonicsignaling on a local area network to a central server. It should beappreciated that the description herein portrays the communications witha central server in an oversimplified manner, and a practical embodimentcan include additional components and suitably configured processinglogic to support known or conventional operating features that are notdescribed in detail herein for the sake of brevity.

A processor may be any microprocessor, application specific integratedcircuit, field programmable gate array, digital signal processor, anysuitable programmable logic device, discrete gate or transistor logic,discrete hardware components, or combinations thereof that has thecomputing power capable of managing the RFID reader or ultrasonicemitters. Processors generally provide the software, firmware,processing logic, and/or other components of the RFID reader orultrasonic emitters that enable their functionality.

A memory can include any of volatile memory elements (e.g., randomaccess memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatilememory elements (e.g., ROM, hard drive, tape, CDROM, etc.), andcombinations thereof. Moreover, the memory can incorporate electronic,magnetic, optical, and/or other types of storage media. Note that thememory can have a distributed architecture, where various components aresituated remotely from one another, but can be accessed by theprocessor. The memory may be utilized to store data associated with RFIDinterrogations, ultrasonic signaling, etc.

A housing combining different network infrastructure can further includeelectronics and components for operation of the antenna arrangement ofthe RFID reader and for operation of the ultrasonic emitters. Theelectronics, components, etc. of the combined network infrastructure maybe disposed or located within the housing. For example, the housing mayenclose electronics and the like for operation of the RFID reader,ultrasonic emitters, wireless access point, as well as other componentsas described herein. The housing can be defined by a common conductiveenclosure that shields internal components from external electricalsignals while providing insulated feedthroughs, apertures, or vias toprovide radio and ultrasonic signals outside of the housing, such as toantenna elements, wired connections, and emitters. For example, theelectronics and components may include electrical connectivity to theantenna feeds through the housing for transmission and reception of RFIDsignals and connection to ultrasonic drivers for transmission ofultrasonic signals.

FIG. 1 illustrates a block diagram of an antenna configuration of oneRFID embodiment of the present invention. An RFID reader 12 can beconnected to a plurality of antenna elements 10 via an antenna switch ordifferent radio ports 14 of the RFID reader. Also, the RFID reader candirect the different radio ports to sequentially communicatively connectonly one antenna element at a time to the RFID reader such that only oneantenna element is operable to transmit/receive at any instant in time.The RFID reader can provide any received tag information it obtains toan access point that can be wired or wirelessly connected to a localarea network (not shown) for inventory purposes, for example. Althougheight antenna elements are shown, there could be any number of elements.Preferably, there is an even number of antenna elements arranged in acircle to radiate outwardly from the circle. As shown in thisembodiment, there are eight antenna elements evenly disposed at 45degree intervals of the circle and connected to an eight-port radio.

FIG. 2 shows a block diagram of another embodiment of the presentinvention including an ultrasonic locationing configuration ofultrasonic emitters 18. The driver of each emitter is controlled by acentral ultrasonic controller 17 that can receive instructions fordriving each emitter from a remote server. These instructions caninclude timing and sound pressure levels for the ultrasonic signals. Thecontroller may share circuitry with the RFID reader. The emitters 18 areco-located with the RFID antenna elements 10 of FIG. 1, as will bedescribed below. Although a combined embodiment as described herein haseight RFID antennas (of FIG. 1) and four ultrasonic emitters (of FIG.2), the actual number of each of the RFID antennas and ultrasonicemitters can vary, depending on the need, application, or coverage. Forexample, there can be one ultrasonic emitter co-located with every RFIDantenna, e.g. eight of each.

Referring to FIG. 3 (exploded emitter view) and FIG. 4 (assembledemitter cutaway view), in one embodiment an RFID antenna includes alinearly polarized, full wavelength loop 20 as the driven element thatis oriented substantially parallel to a conductive reflector panel 26.The loop element 20 can be disposed on a printed circuit board 30 foreasy mounting to the reflector panel using standoffs 22. As is known inthe art, the loop element can be fed by an RF signal at a specific feedpoint 33, depending on the linear polarization desired. In this example,with the gap 24 positioned as shown, and with the element being fed nearthe gap, a vertical polarization can be achieved. With the gap and feedpoint rotated 90 degrees, a horizontal polarization can be achieved.Those skilled in the art will recognize that the loop geometry can bedifferent than what is shown in this exemplary embodiment—as examples,the size can be larger or smaller, the shape does not have to be acircle, the width of the loop does not need to be constant, etc. Theloop element 20 is driven by a balun cable 38 connected at the feedpoint 33 and grounded to the reflector 26 (as shown in FIG. 4). Thebalun cable in this embodiment is one-quarter wavelength long at theoperating frequency. For example, for the North American RFID band,which operates between 902 MHz and 928 MHz, the balun cable length is8.16 cm.

A two-piece ultrasonic emitter 18 is provided. An audio waveguide orhorn 37 with a compression driver (speaker) 34 is mounted to the RFIDreflector panel 26 such that the driver 34 is positioned substantiallybehind the reflector. A speaker flange 32 completes the emitter 18. Theassembled ultrasonic emitter is disposed through an aperture 36 in thereflector panel 26, with the horn 32 extending from the driver 34through the loop element 20 and extending past the loop element 20. Inthis way, the emitter and RFID antenna are co-located. The aperture,emitter, and loop element may or may not be co-located co-axially. Inother words, the emitter may be off axis from the center of the loopelement, as shown. In addition, the emitter need not be aligned exactlyperpendicular to the plane of the loop element. In any event, the driverand horn constitute a two piece assembly, wherein the driver is mountedto the reflector panel, and the driver and horn are configured to beassembled together through the loop antenna element and the aperture.

In accordance with the present invention, the aperture is cut in thereflector to allow the ultrasonic energy to pass through the reflector.A diameter of the aperture is less than one-quarter wavelength of anoperating frequency of the RFID reader loop antenna element. Therefore,having the compression driver smaller in diameter than a quarter RFIDwavelength mitigates the RFID signal passing through the aperture, i.e.the aperture is invisible to the RFID antenna. In addition, the apertureis located in the reflector panel near a minimum E-field area of theRFID reader loop antenna element, in order to further mitigate RFIDsignals passing through the aperture. For example, where a loop elementis fed at a feed point 33 near the gap 24, the antenna presents littleto no E-field near the aperture. Therefore, adding a small component,such as a speaker driver 34, at the reflector panel near a centerline ofthe loop does not adversely affect the loop antenna's performance.Accordingly, since the ultrasonic emitter is positioned in the lowE-field region of the loop antenna, RFID functionality is not affected.

The reflector panel 26 may have holes cut out to provide electricalconnections therethrough. Furthermore, the geometric details of the loopand reflector panel may be different for differing antennapolarizations. It should also be recognized that a partial circleantenna configuration can be used successfully in the present invention,other than the full circle embodiment shown, to provide a substantiallylinear polarization. Typically, the physical shape, size, andconfiguration of the antenna geometry should be resonant at 915 MHz,which is a standard frequency for RFID applications. For European RFIDapplications, the physical shape, size, and configuration of the antennageometry should be resonant at 865 MHz.

In the 915 MHz example shown in FIGS. 3 and 4, each loop element can beflat and approximately 10 centimeters in diameter. The distance of theloop element from the reflector panel is approximately 3.175centimeters. Note that there are other combinations of spacing, loopelement diameter, and reflector panel size that result in a properlytuned and matched 915 MHz system. Also, the loop element does not needto be flat. For example, it may be contoured to follow a curved shape ofa conical reflector. In addition, although a circularly polarizedantenna could be used, circularly polarized antennas need an additional3 dB of circular gain to match the gain of their linear polarizedequivalents, which would result in a significantly larger antennaarrangement and housing.

It should be noted that the size values are approximate, and they couldall be varied to affect a different antenna gain, frequency match, orradiation pattern. The use of a reflector panel placed behind the loopelement and having a spacing therebetween helps to reflect back most ofthe RF energy, making the antenna element a high gain antenna system.The reflector panel takes energy that is directed backwards, towards itfrom the loop element and redirects it, combining it with the directlyradiated pattern that was already directed forward. The result is a highgain, directional antenna.

A length of the ultrasonic emitter horn extending from the reflectorpanel is approximately 4.5 centimeters. As shown, it is envisioned thatthe ultrasonic emitter is a two-piece design. A compression driver 34having an externally threaded tweeter cup with an audio waveguide orhorn 37 can assemble to the reflector panel 26. This assembly extendsthrough a hole in the loop antenna 20 printed circuit board 30 and theaperture 36. An internally threaded speaker flange 32 screws to thetweeter cup with horn 37 to complete the assembly of the emitter. Thespeaker flange 32 serves as a baffle as well as a protective cover forcompression driver 34. It should be recognized that these two partscould be attached is several other ways including snap connectors, twistlocks, screws, etc. It should also be recognized that the tweeter cupwith horn 37 and speaker flange 32 can be split differently with the endcombined result being the same or very similar. It should also berecognized that a separate embodiment can have custom shaped waveguidesfor specific environments as required for performance. In this way, thewaveguide provides an optimized energy spread out onto a “listeningplane” of the environment where mobile devices can pick up a specificultrasonic frequency signal of the emitters (as shown in FIG. 8 whichshows a mobile device and a theoretical listening plane for which amobile device would receive transmission from the ultrasonic emitters.This figure also shows the orientation (vertical angular offset) for theultrasonic emitters in this embodiment).

In this way, the present invention provides the advantage that the RFIDloop antenna and ultrasonic emitter can be co-located without taking upany more spatial volume of an enclosure of the housing, which frees upcritical spatial volume for other features, such as a video camera andthe like.

In the configuration shown in FIG. 3 the loop element 20 and reflectorpanel 26 are spaced from each other using insulating spacers orstandoffs 22 therebetween. However, it is envisioned that the loopelement need not be mechanically coupled directly to the reflectorpanel, but instead can be mechanically coupled directly to theultrasonic emitter 18, which is in turn mechanically coupled to thereflector panel 26. Using the ultrasonic emitter as the mountingstructure for the loop element eliminates the need for a separatemounting structure, thereby reducing the number of parts, lowering cost,and simplifying the design.

FIG. 5 shows a perspective view of an eight element RFID antennaconfiguration with four co-located ultrasonic emitters 18, in accordancewith some embodiments of the present invention. This embodiment utilizesa plurality of the reflector-backed RFID linearly polarized loopantennas 20 (such as those represented in FIG. 3) arranged in a circle(eight antennas spaced at 45 degree intervals) to achieve 360 degrees ofcoverage. Some of the loop antennas include a co-located ultrasonicemitter to form the arrangement of FIG. 3. In one embodiment, all(eight) antenna configurations include an ultrasonic emitter. In anotherembodiment, half of the antenna configurations include an ultrasonicemitter (as shown). It should be recognized that any number ofultrasonic emitter and/or RFID antennas could be used. The reflectorpanels, emitters, and antennas are angled approximately fifteen degreesfrom the vertical.

All the reflector panels 26 are electrically joined together, along witha conductive top 50 and bottom 52, to define a common reflector box orhousing 16. The reflector box isolates the radiated RF energy of theantenna elements from the ultrasonic emitter circuitry. The centralhousing 16 can be, but is not limited to, a square, rectangular,trapezoidal, or a conic section. For example, the central housing 16 canhave a faceted embodiment described by a trapezoidal pyramidal sectionwith planar reflector panels (as shown) that acts as one commonreflector panel and ground plane for all the antennas as well as anelectrical ground for enclosing the other electronics located inside thehousing, including drive circuitry for both the RFID reader loop antennaelements and ultrasonic emitters. Alternatively, the central housing canbe a continuous truncated conical surface. In this embodiment, theantenna arrangements may be built as individual modules that are thenmechanically assembled to a central housing or frame with the top 50 andbottom 52. The configuration shown, when fully enclosed, results in anoverall maximum dimension of about 48 centimeters wide and about 18centimeters tall with the housing portion 16 having a maximum dimensionof about 38 centimeters wide.

In the configuration shown in FIG. 5, numerous RF simulations were runand physical RF mockups of the system were built, and the testingvalidates the concepts associated with the antenna arrangement of thepresent invention. This configuration provides the ability to read allRFID tags near the RFID reader while providing unobstructed ultrasoniclocationing. The RFID reader and ultrasonic controller can be wirelesslycontrolled using existing WLAN infrastructure.

FIG. 6 is a perspective diagram of an exemplary retail environment withan RFID reader/ultrasonic system housing enclosure 60 of FIG. 5 in aceiling-mounted overhead configuration. The present invention isconfigured to provide wireless interrogation of a plurality of RFID tagslocated on or affixed to a plurality of items 62, while also providingultrasonic locationing of mobile devices 64. The housing enclosure 60may be mounted to a ceiling or other overhead fixture in the retailenvironment. The retail environment is shown solely for illustrationpurposes, and the antenna arrangement of the present invention may beused in any environment including a warehouse, manufacturing facility,file room, storage area, and the like. The antennas of the RFID readerare configured to provide a far field radiation pattern covering thefloor of the environment, while the ultrasonic emitters are configuredto provide a substantially uniform listening plane for mobile devicemoving within the environment. Typically, the housing is mounted on aceiling of the environment, approximately fifteen feet above the floor.The antennas and emitters are angled downwardly, approximately fifteendegrees from vertical (as represented in FIGS. 5 and 8). In this way,the emitters can communicate with a mobile device 64 that is beingcarried by a person at a typical carrying height defined herein as alistening plane, which is a theoretical plane above the floor wherecarried devices can receive ultrasonic transmission.

Referring to FIG. 7, the present invention describes a method forco-locating a Radio Frequency Identification (RFID) device andultrasonic device. A first step 70 includes providing at least one RFIDreader loop antenna element oriented parallel to a reflector panel.

A next step 72 includes providing at least one ultrasonic emitterincluding a driver and a horn, wherein each ultrasonic emitter isdisposed through an aperture in the reflector panel with the hornextending through the loop element. A diameter of the aperture is lessthan one-quarter wavelength of an operating frequency of the RFID readerloop antenna element. The aperture is located in the reflector panelnear a minimum E-field area of the RFID reader loop antenna. The driverand horn constitute a two piece assembly, wherein the driver and hornare configured to be assembled together through the loop antenna elementand the aperture element. A length of the horn from the reflector panelis approximately 4.5 centimeters and a distance of the loop element fromthe reflector panel is approximately 3.175 centimeters.

A next step 74 includes mounting the antenna element and emitter on aceiling of an environment, with the ultrasonic emitter angledapproximately fifteen degrees downwardly from the vertical.

Advantageously, the present invention provides an integration techniquethat allows two locationing technologies to occupy the same space,thereby providing a significant competitive advantage. By mounting thesource of the ultrasonic energy to the back of the RFID reflector plateand passing the energy through a convenient geometric opening and lowE-field area of the RFID driven element, isolation between the twosystems is very high resulting in each system being invisible to theother. Note that both the length of the waveguide and the spacingbetween the antenna driven element and reflector are optimized such thatthe two technologies can coexist in a shared dimension. As a result, thepresent invention allows co-location of both locationing systems as wellas a means to secure and assemble both systems' components within asminimal of a space as feasible for the required performance (RFIDantenna gains as well as proper speaker size for sufficient SoundPressure Level, polar sound energy pattern, and radial symmetry of soundenergy about the bore sight axis for the emitter).

In the foregoing specification, specific embodiments have beendescribed. However, one of ordinary skill in the art appreciates thatvarious modifications and changes can be made without departing from thescope of the invention as set forth in the claims below. Accordingly,the specification and figures are to be regarded in an illustrativerather than a restrictive sense, and all such modifications are intendedto be included within the scope of present teachings.

The benefits, advantages, solutions to problems, and any element(s) thatmay cause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeatures or elements of any or all the claims. The invention is definedsolely by the appended claims including any amendments made during thependency of this application and all equivalents of those claims asissued.

Moreover in this document, relational terms such as first and second,top and bottom, and the like may be used solely to distinguish oneentity or action from another entity or action without necessarilyrequiring or implying any actual such relationship or order between suchentities or actions. The terms “comprises,” “comprising,” “has”,“having,” “includes”, “including,” “contains”, “containing” or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchthat a process, method, article, or apparatus that comprises, has,includes, contains a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus. An element proceeded by“comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . .a” does not, without more constraints, preclude the existence ofadditional identical elements in the process, method, article, orapparatus that comprises, has, includes, contains the element. The terms“a” and “an” are defined as one or more unless explicitly statedotherwise herein. The terms “substantially”, “essentially”,“approximately”, “about” or any other version thereof, are defined asbeing close to as understood by one of ordinary skill in the art, and inone non-limiting embodiment the term is defined to be within 10%, inanother embodiment within 5%, in another embodiment within 1% and inanother embodiment within 0.5%. The term “coupled” as used herein isdefined as connected, although not necessarily directly and notnecessarily mechanically. A device or structure that is “configured” ina certain way is configured in at least that way, but may also beconfigured in ways that are not listed.

It will be appreciated that some embodiments may be comprised of one ormore generic or specialized processors (or “processing devices”) such asmicroprocessors, digital signal processors, customized processors andfield programmable gate arrays (FPGAs) and unique stored programinstructions (including both software and firmware) that control the oneor more processors to implement, in conjunction with certainnon-processor circuits, some, most, or all of the functions of themethod and/or apparatus described herein. Alternatively, some or allfunctions could be implemented by a state machine that has no storedprogram instructions, or in one or more application specific integratedcircuits (ASICs), in which each function or some combinations of certainof the functions are implemented as custom logic. Of course, acombination of the two approaches could be used.

Moreover, an embodiment can be implemented as a computer-readablestorage medium having computer readable code stored thereon forprogramming a computer (e.g., comprising a processor) to perform amethod as described and claimed herein. Examples of suchcomputer-readable storage mediums include, but are not limited to, ahard disk, a CD-ROM, an optical storage device, a magnetic storagedevice, a ROM (Read Only Memory), a PROM (Programmable Read OnlyMemory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM(Electrically Erasable Programmable Read Only Memory) and a Flashmemory. Further, it is expected that one of ordinary skill,notwithstanding possibly significant effort and many design choicesmotivated by, for example, available time, current technology, andeconomic considerations, when guided by the concepts and principlesdisclosed herein will be readily capable of generating such softwareinstructions and programs and ICs with minimal experimentation.

The Abstract is provided to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin various embodiments for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separately claimed subject matter.

What is claimed is:
 1. An apparatus including a co-located RadioFrequency Identification (RFID) device and ultrasonic device,comprising: an RFID reader loop antenna element disposed away from areflector panel, the reflector panel configured to redirect at leastsome radio frequency energy generated by the loop antenna element in apredetermined direction, the loop antenna element overlaying thereflector panel and being offset from the reflector panel by a gap; andan ultrasonic emitter including a driver and a horn, wherein theultrasonic emitter is disposed through an aperture in the reflectorpanel with the horn extending through the loop antenna element.
 2. Theapparatus of claim 1, wherein a diameter of the aperture is less thanone-quarter wavelength of an operating frequency of the RFID reader loopantenna element.
 3. The apparatus of claim 1, wherein the aperture islocated in the reflector panel near a minimum E-field area of the RFIDreader loop antenna element.
 4. The apparatus of claim 1, wherein thedriver and horn constitute a two piece assembly, wherein the driver andhorn are configured to be assembled together through the loop antennaelement and the aperture.
 5. The apparatus of claim 1, furthercomprising a plurality of co-located RFID reader loop antenna elementsand ultrasonic emitter horns, wherein the reflector panels of the RFIDreader loop antenna elements are electrically joined together to definea common reflector box, and wherein the reflector box defines a housingthat contains circuitry for both the RFID reader loop antenna elementsand ultrasonic emitters and acts as an electrical ground for the RFIDreader loop antenna elements that are positioned to radiate outwardlyfrom the reflector box.
 6. The apparatus of claim 1, wherein theapparatus is configured to be mounted on a ceiling of an environment,with the ultrasonic emitter angled approximately fifteen degreesdownwardly from the vertical.
 7. The apparatus of claim 1, wherein alength of the horn from the reflector panel is approximately 4.5centimeters and a distance of the loop antenna element from thereflector panel is approximately 3.175 centimeters.
 8. An apparatusincluding a co-located Radio Frequency Identification (RFID) device andultrasonic device, comprising: a plurality of RFID reader loop antennaelements each disposed away from a respective reflector panel, whereinthe reflector panels are electrically joined together to define a commonreflector box that defines a housing that contains circuitry for boththe RFID devices and ultrasonic devices and acts as an electrical groundfor the RFID reader loop antenna elements; and a plurality of ultrasonicemitters each including a driver and a horn, wherein each ultrasonicemitter is disposed through an associated aperture in the reflectorpanel with the horn extending through a co-located antenna loop element,wherein a diameter of the apertures is less than one-quarter wavelengthof an operating frequency of the RFID reader loop antenna elements, andwherein the apertures are located in the reflector box near a minimumE-field area of the associated RFID reader loop antenna element.
 9. Amethod for co-locating a Radio Frequency Identification (RFID) deviceand ultrasonic device, the method comprising the steps of: providing atleast one RFID reader loop antenna element disposed away from areflector panel, the reflector panel configured to redirect at leastsome radio frequency energy generated by the loop antenna element in apredetermined direction, the loop antenna element overlaying thereflector panel and being offset from the reflector panel by a gap; andproviding at least one ultrasonic emitter including a driver and a horn,wherein each ultrasonic emitter is disposed through an aperture in thereflector panel with the horn extending through the loop antennaelement.
 10. The method of claim 9, wherein a diameter of the apertureis less than one-quarter wavelength of an operating frequency of theRFID reader loop antenna element.
 11. The method of claim 9, wherein theaperture is located in the reflector panel near a minimum E-field areaof the RFID reader loop antenna element.
 12. The method of claim 9,wherein the driver and horn constitute a two piece assembly, wherein thedriver and horn are configured to be assembled together through the loopantenna element and the aperture.
 13. The method of claim 9, furthercomprising mounting the loop antenna element and emitter on a ceiling ofan environment, with the ultrasonic emitter angled approximately fifteendegrees downwardly from the vertical.
 14. The method of claim 9, whereina length of the horn from the reflector panel is approximately 4.5centimeters and a distance of the loop antenna element from thereflector panel is approximately 3.175 centimeters.